On Saturday, Sam Kanizay went for a swim at a beach in Melbourne. About 30 minutes later, the 16-year-old walked out of the water with his feet and ankles covered in what looked like hundreds of little pin holes that were bleeding profusely.

Kanizay lays in a bed with his feet bleeding.

Jarrod Kanizay/AP

Kanizay holding a jar with creatures in it speaks from a bed of a hospital where he is treated.

Close-up photo of an amphipod navigating among newly-laid yellow perch eggs from the brackish waters of Mattawoman Creek in Indian Head, MD.

Kanizay’s feet are seen covered in what looked like hundreds of bleeding little pin holes. A teenager who went for a swim at a Melbourne beach and emerged with his feet covered in blood has stumped marine experts.

Thousands of tiny bites were found all over Sam’s feet, baffling doctors and nurses at first. But the problem has now been traced to thousands of tiny flesh-eating parasites, normally attracted to decaying meat.

Dr. Ian Horsfall, a marine biologist with Swansea University, believes the teen may have been attacked by amphipods.

The crustaceans are related to shrimp and lobster and there are about 10,000 species of them, he said. They range in size from one millimetre to about 30 centimetres, although the really large amphipods are usually found in the deep sea.

The amphipods have no venomous properties and will not cause lasting damage.

“They are in the sand or sea bed during the day and come out at night,” Horsfall said. “Occasionally there can be large swarms of them and I’m guessing he happened to walk into a big swarm of them and they decided to have a feast on his feet.”

Horsfall said most people have probably come across these tiny creatures at night — when they pop out of the sand.

“You’ll probably find them floating in your drink at night….and then they end up drowning in your cup,” he said.

WATCH: Australian teen describes seeing feet bloodied after dip in the ocean

The chance of stepping on a swarm of them is a very chance incident, he said. The teenager was simply at the wrong place and at the wrong time.

“I’ve never seen anything like this,” one marine expert told a local TV program. Thomas Cribb, a parasite expert at the University of Queensland, told the Associated Press that the creatures were “not a parasite I’ve ever come across.”

Fortunately, Kanizay is now in recovery mode and has a word of advice for people at his local beach.

“Maybe don’t go icing your feet there anytime soon,” he said.

Are they found in Canada?

Beach-goers in Canada probably don’t have to worry about this happening to them, according to Taz Stuart, an entomologist for Poulin’s Pest Control Services in Winnipeg.

“I’ve never heard of this happening in Canada,” he said.

Stuary said the amphipods in Australia would be similar to sand fleas in Canada, which could be found on most beaches.